need to know how to solve the following....

a gas filled weather balloon floating in the atomsphere has an initial volume of 850 L. The balloon rises to a region where the pressure is 56 kPa and its volume expands to 1700 L. If the temperature remains the same, what was the initial pressure on the weaher balloon?

1 answer

Use Boyles law

P1V1 = P2V2

Answer 112 kPa

(850)(x)=(1700)(56) <--- Equation